Sewing-machine tension



(No Model.)

A. SPEAR.

SEWING MACHINE TENSION.

Patented Aug. 8, 1882.

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UNITED STATES PATENT OFFICE.

ARTHUR SPEAR, OF CHICAGO, ILLINOIS.

SEWING-MACHINE TENSION.

SPECIFICATION forming part of Letters Patent: N0. 262,253, dated August8, 1882. Application filed November 23, 1881. (No model.)

To all whom it may concern Be it known that I, ARTHUR SPEAK, of Ohicago,in the county of (look and State of Illinois, have invented certain newand useful Improvements in Sewing-Machine Tensions, of which thefollowing, in connection with the accompanying drawings, is aspecification.

In the drawings, Figure 1 is a side view of the inner side of thedetachable part or plate of a sewing-machine head. Fig. 2 is a sectionin the plane of the line a: m. Fig.3 is a detail in perspective of thetension-lever, and Fig. 4 represents a modification of construction.

Like letters of reference indicate like parts.

A is the removable part orplate of a sewingmachine head, and B is thetension-regulating screw entering the said part. 0 O are thetension-disks, and D is the bolt upon which theyaremounted.Eisthetension-lever. The upper end of this lever is inclined, as shown,to receive the lower end of the screw B, which impinges upon thisinclined part, so that the position or tension of the lever may bealtered by turning the screw in and out of the head in the usual manner,it being understood that the lever E is made of spring metal, isfulcrumed on the part A, and engages the bolt D. In the plate A is ashoulder, a, and a is a corresponding shoulder bent in the lever E andengaging the shoulder a, as shown. By this means the lever E isprevented from being pushed downward by the screw B, and at the sametime has such a bearing on the plate A as to be capable of a tiltingmovement, which will act with greater or less force on the bolt D, andconsequently on the disks 0 G, as the screw B is turned. I thus avoidthe liecessity of using a screw for connecting the lever E to the plateA and of making a corresponding screw-hole in the said plate. To preventa lateral movement of the upper end of the lever E,it should be therewide enough to fill or nearly fill the recess which receives it, asshown. The lower part of the lever may then be made tapering, as thelower end is held in place by the bolt D. This form of lever results ingood spring action; but I do not regard a wide upper end and a taperinglower part as absolutely essential features of my invention.

Heretofore, so far as I am aware, the screw B has been made beveled,rounded, or tapering at its lower end to avoid the liability of itsstriking the upper edge of the lever E. I avoid this liability, when ascrew with a square edge is used. by curling up the edges of the upperpart of the lever, as shown at a a, so that these edges will meet thefixed part of the head of the machine when the tension is very loose orwhen the screw B is drawn away from the lever, and thus prevent theupper edge of the lever from moving underneath the lower end of thescrew. These curled-up parts also aid in keeping the upper end of thelever in its proper place.

In Fig. 4 I have shown a modification in the construction of thespring-leverE. This modification consists of the lateral extensions 1)b, which serve, in lieu of the shoulder a, for supporting the lever E,the part Abeing notched, as shown at b b, to receive the extensions 1) band support the lever E, so that the screw B will act upon it as before.It is obvious that either the shoulder a or the extensions 11 I) serveas a bearing on which the lever may be tilted by the screw B. When theextensions or bearing-arms b b are employed the shoulder a will not beessential. The extensions 1) I) also perform the functions of shouldersin preventing the lever from slipping longitudinally, and may thereforealso be termedshoulders, which rest against the lower shoulders formedby the notches b b, and thus prevent the leverE from being pusheddownward by the regulating-screw B. It is not absolutely necessary thatthe lever E should be fulcrumed on its shoulders.

I am aware that tilting tension springs or levers have heretofore beenemployed in connection with a regulating-screw and the disks 0 U in theclass of sewing-machine tensions to which that herein described belongs;but so far as I am aware those springs or levers have heretofore beenpierced to receive a screw entering the plate A, thereby preventing thespring from slipping longitudinally, and I do not here intend to claimsuch; but,

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. The combination, in a sewing-machine tension, of the shoulderedface-plate A, the

shouldered tilting spring-lever E, the regulattension, of the face-plateA, the screw B, the ing-screw 13, the bolt D, and the disks 0 O, disks GO, the bolt D, and thelever E, hzwing I0 the said shoulders beinglocated to engage curled-up edges a a, substantially as and each other,and thereby prevent the said lever for the purposes specified.

5 from slipping longitudinally when acted on by ARTHUR SPEAR.

the said screw, substantially as and for the Vitnesses: purposesspecified. F. F. VVARNEB,

2. The combination, in a sewing-machine H. FRANKFURTER.

